MLA
Wesley, John William. Letter from John William Wesley to Charles Wesley Junior, [London] - January 2, 1823. 1823. Pitts Theology Library, Box 3, Folder 56. https://digital.library.emory.edu/purl/6386hdr8bz-cor.
APA, 6th edition
Wesley, J. W. (1823). Letter from John William Wesley to Charles Wesley junior, [London] - January 2, 1823 (Box 3, Folder 56) [Correspondence]. Pitts Theology Library. https://digital.library.emory.edu/purl/6386hdr8bz-cor.
Chicago
Wesley, John William. “Letter from John William Wesley to Charles Wesley Junior, [London] - January 2, 1823.” Correspondence. Wesleyana Collection, 1823. Box 3, Folder 56. Pitts Theology Library. https://digital.library.emory.edu/purl/6386hdr8bz-cor.